Biology subjects

Behrenbruch, C.

Publications and source records attributed to Behrenbruch, C..

4 recordsLinked to original sources

bioRxiv2025

Netrin-1 regulates colorectal cancer stem cell self-renewal via a TFF3 dependent paracrine survival mechanism

BackgroundMetastatic colorectal cancer (mCRC) is associated with high recurrence rates and resistance to conventional treatments, largely driven by cancer stem cells (CSCs) that contribute to tumor progression and therapeutic evasion. This study aims to investigate the role of netrin-1 and its dependence receptor UNC5B in regulating CSC self-renewal in mCRC and explore their potential as therapeutic targets. MethodsWe used patient-derived liver metastasis organoids (PDOs) to examine the effects of netrin-1 on CSC self-renewal. The role of UNC5B was evaluated by silencing its expression using CRISPR and assessing the impact on CSC apoptosis in response to an anti-netrin-1 blocking antibody (NP137) using extreme limiting dilution assays (ELDAs). Single-cell RNA sequencing was employed to explore the molecular mechanisms behind netrin-1/UNC5B regulation of CSC fate. Clinical data from a patient with mCRC were used to validate the findings. ResultsNetrin-1 promoted CSC self-renewal by inhibiting apoptosis, a process reversed by NP137. UNC5B was identified as the primary receptor mediating this effect, as its silencing eliminated Netrin-1-induced self-renewal. Trefoil Factor 3 (TFF3), secreted by UNC5B-expressing cells, plays a key role in netrin-1-induced CSC self-renewal. Clinical trial data from a patient with mCRC showed a reduction in TFF3 and stemness genes expression after treatment with NP137. Furthermore, combining NP137 with FOLFOX chemotherapy enhanced cell death and inhibited tumor growth in PDO xenograft models. ConclusionThis study identifies the netrin-1/UNC5B/TFF3 axis as a critical regulator of CSC self-renewal in mCRC and suggests that targeting this pathway with NP137, in combination with chemotherapy, could provide a promising therapeutic approach for mCRC patients.

cancer biology↗

bioRxiv2022

A new highly-specific Natural Killer cell-specific gene signature predicting recurrence in colorectal cancer patients.

The protective role of Natural Killer (NK) cell tumour immunosurveillance has long been recognised in colorectal cancer (CRC). However, as most patients show limited intra-tumoral NK cell infiltration, improving our ability to identify those with high NK cell activity might aid in dissecting the molecular features which could trigger strong response to NK cell-mediated immune killing. Here, a novel CRC-specific NK cell gene signature capable of inferring NK cell load in primary tissue samples was derived and validated in multiple patient CRC cohorts. The specificity of the signature is substantiated in tumour-infiltrating NK cells from primary CRC tumours at the single cell level, and the expression profile of each constituent gene is explored in NK cells of different maturation states, activation status and anatomical origin. Thus, in contrast with other NK cell gene signatures that have several overlapping genes across different immune cell types, our NK cell signature has been extensively refined to be specific for CRC-infiltrating NK cells and includes genes which identify a broad spectrum of NK cell subtypes. Moreover, it was shown that this novel NK cell signature accurately discriminates murine NK cells, demonstrating the potential applicability of this signature when mining datasets generated from both clinical and animal studies. Differential gene expression analysis revealed tumour-intrinsic features associated with NK cell inclusion versus exclusion in CRC patients, with those tumours with predicted high NK activity showing strong evidence of enhanced chemotactic and cytotoxic transcriptional programs. Furthermore, survival modelling indicated that NK signature expression is associated with improved survival outcomes in two large cohorts of primary CRC patients. Thus, scoring CRC samples with this refined NK cell signature might aid in identifying patients with high NK cell activity who could be prime candidates for NK cell directed immunotherapies.

cancer biology↗

bioRxiv2021

Targeting of TP53-independent cell cycle checkpoints overcomes FOLFOX resistance in Metastatic Colorectal Cancer

Patients with colorectal cancer (CRC) frequently develop liver metastases during the course of their disease. A substantial proportion of them receive neoadjuvant FOLFOX (5-Fluorouracil, Oxaliplatin, Leucovorin) prior to surgery in an attempt to enable successful surgical removal of their metastases and to reduce the risk of recurrence. Yet, the majority of patients progress during treatment or recur following surgery, and molecular mechanisms that contribute to FOLFOX resistance remain poorly understood. Here, using a combination of phenotypic, transcriptomic and genomic analyses of both tumor samples derived from patients with metastatic CRC and matching patient-derived tumor organoids (PDTOs), we characterize a novel FOLFOX resistance mechanism and identify inhibitors that target this mechanism to resensitize metastatic organoids to FOLFOX. Resistant PDTOs, identified after in vitro exposure to FOLFOX, exhibited elevated expression of E2F pathway, S phase, G2/M and spindle assembly checkpoints (SAC) genes. Similar molecular features were detected in CRLM from patients with progressive disease while under neoadjuvant FOLFOX treatment, highlighting the relevance of this finding. FOLFOX resistant PDTOs displayed inactivating mutations of TP53 and exhibited transcriptional features of P53 pathway downregulation. We found that they accumulated in early S-phase and underwent significant DNA damage during FOLFOX exposure, thereafter arresting in G2/M while they repaired their DNA after FOLFOX withdrawal. In parallel, results of a large kinase inhibitor screen indicated that drugs targeting regulators of the DNA damage response, G2M checkpoint and SAC had cytotoxic effects on PDTOs generated from patients whose disease progressed during treatment with FOLFOX. Corroborating this finding, CHK1 and WEE1 inhibitors were found to synergize with FOLFOX and sensitize previously resistant PDTOs. Additionally, targeting the SAC master regulator MPS1 using empesertib after exposure to FOLFOX, when cells accumulate in G2M, was also very effective to kill FOLFOX-resistant PDTOs. Our results indicate that targeted and timely inhibition of specific cell cycle checkpoints shows great potential to improve response rates to FOLFOX in patients with metastatic CRC, for whom therapeutic alternatives remain extremely limited.

cancer biology↗

bioRxiv2020

The ratio of exhausted to resident infiltrating lymphocytes is prognostic for colorectal cancer patient outcome

Immunotherapy success in colorectal cancer (CRC) is mainly limited to patients whose tumours exhibit high microsatellite instability (MSI). However, there is variability in treatment outcomes within this group, which is in part driven by the frequency and characteristics of tumour infiltrating immune cells. Indeed, the presence of specific infiltrating immune cell subsets has been shown to correlate with immunotherapy responses and is in many cases prognostic of treatment outcome. Tumour-infiltrating lymphocytes (TILs) can undergo distinct differentiation programs, acquiring features of tissue-residency or exhaustion, a process during which T cells upregulate inhibitory receptors such as PD-1 and loose functionality. While residency and exhaustion programs of CD8 T cells are relatively well-studied, these programs have only recently been appreciated in CD4 T cells and remain largely unknown in tumour-infiltrating natural killer (NK) cells. In this study, we use single cell RNA-seq data to identify signatures of residency and exhaustion in CRC infiltrating lymphocytes, including CD8, CD4 and NK cells. We then test these signatures in independent single cell data from tumour and normal tissue infiltrating immune cells. Further, we use versions of these signatures designed for bulk RNA-seq data to explore tumour intrinsic mutations associated with residency and exhaustion from TCGA data. Finally, using two independent transcriptomic data sets from patients with colon adenocarcinoma, we show that combinations of these signatures, in particular combinations of NK activity signatures, together with tumour-associated signatures, such as TGF-{beta} signalling, are associated with distinct survival outcomes in colorectal cancer patients.

cancer biology↗